Assessing the ecological quality status of arid mangroves in the Gulf of Oman, Iran, using benthic indices of AMBI, M-AMBI, and BENTIX

Polychaetes are suitable indicators to evaluate the benthic ecological status and respond to natural and anthropogenic. We evaluated the ecosystem health of the mangroves of Azini and Gwadar based on benthic indices including AMBI, M-AMBI, and BENTIX using polychaete communities. The results showed that in both regions, EcoQ classifications ranged from "high" to "moderate" in BENTIX, "good" to "excellent" in AMBI, and "good" in M-AMBI. The M-AMBI was significantly correlated with sediment variables, including total organic matter (TOM), total organic carbon (TOC), and silt/clay. The result revealed a significant correlation between the biotic indices and the TOC content of sediments. According to the results, TOC can be used as a descriptor and indicator to evaluate the health of mangrove ecosystems in relation to benthic indices. In addition, it is necessary to combine several indices to assess the status of ecosystems

Statistical Analysis of the Effect of Nanoparticles Volume Fraction on Turbulent Forced Convective Heat Transfer Coefficient of Nanofluid in a Circular Tube

In this paper, the statistical analysis of the effect of nanoparticles volume fraction on one of the most important thermal characteristics turbulent flow of nanofluid i.e. convection heat transfer coefficient, inside a circular tube with uniform wall heat flux is investigated numerically. Also, water as a base fluid and Al2O3 as suspended particles with a diameter of 36 nm are considered. Heat transfer characteristics are computed using the solution of elliptic equations based on discrete the finite volume method and the second order upwind. The relationship between pressure and velocity using SIMPLEC algorithm is established. In this study, the variation of volume fraction of nanoparticles is assumed in the range of 0 to 6%. The best probability distribution function of the heat transfer parameters are selected using chi square test that various probability distribution such as: Gamma, Normal, Lognormal, Gumbel, and Frechet are evaluated based on numerical analysis of tube flow. After reviewing the results, it was found that with increasing volume fraction of nanoparticles, the convective heat transfer coefficient increases. On the other hand, the convective heat transfer coefficients with regard to variation of volume fraction of nanoparticles follow Gumbel Max probability distribution function

Determination of aluminium bioaccumulation in liver, gill and muscle tissues of the common carp (Cyprinus carpio)

Aluminium is an abundant metal on earth and its concentration has increased in aquatic environments as a result of natural and industrial activities. The aim of this study was to examine the bioaccumulation of aluminium in tissues of liver, gill and muscle of common carp (Cyprinus carpio) that was used in concentrations of 1, 2, 4 and 6 mg/L in vitro. The metal in the tissues after chemical digestion was measured by atomic absorption spectrophotometer. Compare the amount of aluminium accumulation in the tissues of gill, liver and muscle showed significant differences in different concentrations of aluminium with the control group (P<0.05). The highest amount of aluminium accumulation in gill, muscle and liver were 51.3 ± 0.4, 20.86 ± 0.5 and 11.50 ± 0.28 μg/g D.W at a concentration of 6 mg (96 hours), respectively, and the lowest were 1.2 ± 0.01, 2.9 ± 0.1 and 0.18 ± 0.3 μg/g D.W in the control group. The results showed that the highest bioaccumulation of aluminium in different tissues were gill, liver and muscle, respectively. Also, it was found that with increasing concentration of aluminium in the environment, bio-accumulation index decreased because of probably physiological activity of tissues. Significant relationship was observed between exposed time and aluminium accumulation in muscle and liver tissue. The gill is the target organ for aluminium that can be used as an indicator of environmental contamination

Changes in metabolic enzymes levels exposed to zinc and cadmium in the snow trout (Schizothorax zarudnyi)

Nowadays, the entrance of pollutants including heavy metals in environment threatens the life of aquatic animals. In this study, the effect of zinc chloride (6 mg/l) and cadmium chloride (5 mg/l) exposure were studied on the activity of some metabolic enzymes in the liver, gills, brain and muscle in Snow trout (Schizothorax zarudnyi). The results showed that zinc caused a significant increase in AChE activity in the brain, AST activity in the liver and muscle and ALP activities only in the liver (p˂0.05). Exposure to cadmium significantly decreased acetylcholinesterase in the brain (p˂0.05). However, ALT activity in the liver and gills and AST activity only in the gills was increased significantly following cadmium exposure. Cadmium stimulatory effects on ALP in tissues were not statistically significant. Based on the above result, in this Species exposed to cadmium showed more toxicity than zinc, and the most sensitivity and susceptibility to the presence of cadmium and zinc in the environment was seen in livers of fish. Assessing levels of metabolic enzymes in the liver tissue and AChE enzyme in the brain tissue of Snow trout has the potential to be used as a suitable indicator to show heavy metal pollution in the aquatic ecosystem

A Review on Natural Convection in Nanofluid Flow

The Heat transfer is performed in three forms including conduction, convection and radiation. Convection is one of the major modes which classifies into three categories: natural, mixed or forced convection. In recent years, much attention was given to the use of natural convection with nanofluid in engineering application, satellite, cooling system, solar collector etc. and many studies were conducted in this area. This paper reviews some results of numerical, experimental and theoretical studies in the field of natural convection heat transfer with nanofluid and application of natural convection. Finally, some suggestions are given for future studies in this area

Identification of the Opportunities for Future Development of Tidal Energy

An overview of status of development of tidal energy is given in this article. To reduce the dependance on fossil fuel and imported energy resources, the need for ocean energy is a global demand in developing countries. The ability to directly extract from the world’s oceans may be in the form of mechanical energy from waves, tides, or currents, or in the form of thermal energy from the sun’s heat. This paper identifies the opportunities for future development of tidal energy

Polychaete Diversity and Functional Trait Composition in Subtropical Mangrove Ecosystems

Polychaetes play a vital role in the structure and functioning of benthic communities in mangrove ecosystems. Nevertheless, our understanding of the diversity and functional structure of polychaete assemblages across different habitats in the mangrove ecosystems along the coast of the Persian Gulf and Gulf of Oman is limited. In this study, we investigated the species and trait composition of polychaetes and environmental variables, in vegetated and mudflat habitats of three subtropical mangroves. The results showed that Neanthes glandicincta was widely distributed across all regions and habitats. The three-factor ANOVA showed that the abundance and taxonomic diversity of polychaetes differed significantly between two habitats and three mangrove ecosystems. The abundance of polychaetes was observed to be higher in mud habitats than in vegetated habitats. There was a significant difference in species and trait composition between different regions and habitats. Vegetated habitats had higher proportions of crawler predatory species that are longer lived (3–5 years), with larger body size (80–100 mm), and are upward conveyors, whereas mudflat habitats had higher proportions of mobile (burrower) omnivore species that are moderately lived (1–3 years), with larger body size (>100 mm), and are biodiffusers. The three-factor ANOVA showed a significant difference in the community weighted mean (CWM) index between two habitats and three mangrove ecosystems. Thus, the species and trait composition of polychaetes depend on the structural complexity of their respective habitats. The DistLM analysis showed that total organic carbon content of the sediment was the main predictor variable influencing species composition, while silt/clay content and salinity were the main predictor variables influencing the traits’ composition. The results showed how the composition of traits and the structure of polychaete communities change in mangrove ecosystems, which can be used for future studies on conservation strategies for mangrove ecosystems throughout the world